Network Working Group W. Sanchez
Request for Comments: 5397 C. Daboo
Category: Standards Track Apple Inc.
December 2008
WebDAV Current Principal Extension
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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Abstract
This specification defines a new WebDAV property that allows clients
to quickly determine the principal corresponding to the current
authenticated user.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . . 2
3. DAV:current-user-principal . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Normative References . . . . . . . . . . . . . . . . . . . . . 4
Sanchez & Daboo Standards Track [Page 1]RFC 5397 WebDAV Current Principal December 20081. Introduction
WebDAV [RFC4918] is an extension to HTTP [RFC2616] to support
improved document authoring capabilities. The WebDAV Access Control
Protocol ("WebDAV ACL") [RFC3744] extension adds access control
capabilities to WebDAV. It introduces the concept of a "principal"
resource, which is used to represent information about authenticated
entities on the system.
Some clients have a need to determine which [RFC3744] principal a
server is associating with the currently authenticated HTTP user.
While [RFC3744] defines a DAV:current-user-privilege-set property for
retrieving the privileges granted to that principal, there is no
recommended way to identify the principal in question, which is
necessary to perform other useful operations. For example, a client
may wish to determine which groups the current user is a member of,
or modify a property of the principal resource associated with the
current user.
The DAV:principal-match REPORT provides some useful functionality,
but there are common situations where the results from that query can
be ambiguous. For example, not only is an individual user principal
returned, but also every group principal that the user is a member
of, and there is no clear way to distinguish which is which.
This specification proposes an extension to WebDAV ACL that adds a
DAV:current-user-principal property to resources under access control
on the server. This property provides a URL to a principal resource
corresponding to the currently authenticated user. This allows a
client to "bootstrap" itself by performing additional queries on the
principal resource to obtain additional information from that
resource, which is the purpose of this extension. Note that while it
is possible for multiple URLs to refer to the same principal
resource, or for multiple principal resources to correspond to a
single principal, this specification only allows for a single http(s)
URL in the DAV:current-user-principal property. If a client wishes
to obtain alternate URLs for the principal, it can query the
principal resource for this information; it is not the purpose of
this extension to provide a complete list of such URLs, but simply to
provide a means to locate a resource which contains that (and other)
information.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
Sanchez & Daboo Standards Track [Page 2]